Electrical linear motors are used to propel vehicles. For example, linear motors are used for maglev trains and other ground-based transportation applications. These types of linear motors are usually of the linear synchronous design, with an active winding on one side of an air-gap and an array of alternate pole magnets on the other side. These magnets can be permanent magnets or energized magnets.
Electrical rotary motors are used to propel vehicles and marine vessels, such as boats and submarines. Electrical rotary motors for marine vessels utilize propellers to transform the rotary motion mechanical energy into working propulsion linear force. One of the disadvantages of utilizing propellers to propel a marine vessel is that the propeller creates a water rotational movement (swirl) in the water, thereby making the vessel more easily detected.
Using electrical linear motors for propelling a marine vessel, submarines, or torpedoes have several advantages over electrical rotary motors. For example, electrical linear motors can produce up to 3000 lbs of linear driving force and therefore can provide increased velocities of the vessels. Also, the acceleration rate of electrical linear motors is up to 10 g. Electrical linear motors directly transform its electrical energy into the ELM propulsion linear force and therefore as a vessel's drive ELMs are simple, requiring few moving parts and not requiring mechanical transmissions, such as propellers. As a result, ELMs are more reliable than rotary motors. The operation of electrical linear motors does not create pollution to the environment and are more energy efficient that electrical rotary motors. The new simple ELM drive can be based on direct current (DC) or alternating current (AC).